Unprotected olefin polymers are known to degrade over time when in contact with a heavy metal. For example, if an unprotected olefin polymer, e.g., polypropylene, is used to cover copper wire, the copper wire will promote or catalyze the scission of the polymer. Accordingly, many compounds have been developed over the years to protect an olefin polymer from such degradation. Among these compounds are various hydrazines.
U.S. Pat. No. 4,043,976 describes a stabilized olefin polymer composition having resistance against deterioration caused by contact with heavy metals such as copper, the composition comprising an olefin polymer and from 0.001 to 5 parts by weight of an N,N′-dibenzoylhydrazine derivative. While demonstrating effectiveness to one degree or another, these hydrazines also demonstrate less than desirable compatibility with many olefin polymers and thus have a tendency to migrate over time out of the polymer composition. This migration reduces the amount of compound in the polymer composition, and this in turn reduces the protection to the olefin polymer or, alternatively, requires that more compound must be used than would otherwise be required if migration was not a problem.